One in every five students in the Nation's schools has significant mental health problems. Mental health and psychosocial problems interfere with the ability of schools to educate, limit students' learning and academic performance, and ultimately interfere with individuals' opportunities to succeed in society. The social-emotional and behavioral precursors to the problems in early elementary school often begin in infancy and toddler hood. In our currently funded study, information was collected about social-emotional and behavioral problems and competencies, language acquisition, and psychosocial risk in an ethnically diverse, representative sample of 1- and 2- year old children. We achieved a response rate of 80 percent in our first year and a retention rate of 92 percent in our second year of data collection. Preliminary findings suggest a prevalence of 11-12 percent for social-emotional and behavioral problems and a prevalence of 17 percent for language delays. In addition, there was significant stability in problems over a 1-year period, with 61 percent of children persisting in the extreme 10th percentile for problem behaviors for their age and sex. Working within a transactional ecological model and informed by developmental psychopathology, we are proposing to follow this unique and diverse sample of children. Specifically, using a longitudinal enriched sample design, we propose to survey parents and teachers (N-1093 to 1158) about child social-emotional problems and competencies, language ability, school functioning, and ecological risk when children are in Kindergarten. Using information about emotional! behavior problems and language functioning, a subsample of children at high risk for psychopathology and school adjustment problems and some children at low risk will be identified for inclusion in Direct Assessments in Kindergarten and Grade 2 (Enriched Sample, N-493 to 513). Teachers of children in the Enriched Sample will be surveyed in Grade 2. The following three outcomes are the focus of the proposed work: 1) emotional/problem behaviors; 2) psychiatric disorders; and 3) school adjustment. Further, we examine the direct and indirect influences of child competence, neurocognitive vulnerability, child sex, and cumulative family/community risk on emotional! behavioral trajectories, psychiatric disorders, and problems in school adjustment. By following this unique representative birth cohort through the critical transition to formal schooling, we hope to understand continuities and discontinuities in emotional/behavioral development and to gather critically needed data that can inform early identification, prevention and intervention efforts.